A High Control Bandwidth Design Method for Aalborg Inverter under Weak Grid Condition

Aalborg Inverter is a kind of high efficient Buck-Boost inverter. Since it may work in "Buck-Boost" mode, the control bandwidth should be high enough to ensure a good performance under any grid condition. However, during the "Boost" operation, the control bandwidth depends much on the grid impedance if the crossover frequency is traditionally chosen lower than the characteristic frequency of system. Thus, the bandwidth cannot satisfy the high bandwidth requirement in the weak grid state. In this paper, a new high control bandwidth design method for Aalborg Inverter is proposed. With the proposed method, the bandwidth and the phase margin of the system can reach to 7 kHz and 36 degree respectively, when the grid impedance changes from 0 to 4.8 mH. Meanwhile, no extra damping measure needs to stabilize the system. Simulation and experimental results on an 110 V/ 1 kW prototype verify the proposed design well.